hi all...proud new owner of a light blue 77....

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Did you try ALL of the blower speeds on the switch? The lo/med/med hi speeds all work off of a resistor in the heater core plenum(box), but the High speed works off of a relay. If you do not have a working blower motor on ANY speed, you may either have a bad blower motor, or a wiring problem. Try checking the connections at the blower motor to make sure the two connection(power & ground) are good. The, you may want to check for voltage at the purple wire on the blower. If you have varying voltage at the wire with the switch on the different speeds settings, then your motor is not good. If no voltage, it's time to start checking out the wiring, and circuitry...


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Joel Adams
C3VR Lifetime Member #56    
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Thnak you very much for your response!

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Adam is that the same set up on the switch for 78-82?  with the high speed taking a different path than the lower speeds?

and the hissing is vacuum leaks. Usually old, missing or disconnected hoses under dash or upper console.

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Jimmy B.
Just can't wait to get on the road again.

 
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Afaik, Gilbert, all GM products of the era with A/C had the same type system, as far as the high blower goes. It always runs thru a relay. If it did not, the wiring would loose all of the smoke, and the switch would melt from the high amperage. This is why the high speed blower relay is mounted fairly close to the blower motor.


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Joel Adams
C3VR Lifetime Member #56    
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

It sounds like you may have at least 2 different problems.  The blower fan is electric and operated from the switch, resistor and relay as Joel mentioned.  The hissing part of the problem is probably from the vacuum part of the system which operates the blend doors which route air to different areas dependng on where you move the sliders for defrost, heat, a/c etc.  Lots of vacuum hoses attach to the control console.  The only way to know where the hissing is from is to remove the side panels and have a look / listen.

I was going to post a similar problem but I'll ask here if I may.

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Case75,

Thanks Crossfire for the pic. The relay and resister are in the same place on mine. I'll give that a try. If I number the fan positions 0,1,2,3,4 with 0 being off, it is position 1 & 2 that are not working.

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I would lean toward the resistor being the problem on yours, case75. If High speed works, the relay is good. If only one or two of the lower speeds are working, then the resistor, or the switch is the problem.

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Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

Thanks Joel, I'll look at that. Always appreciate your knowledge. I wonder if I buggered the switch when I had the controls apart?

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